If you would like, you can disable the service at WHM > Service Configuration > Service Manager: "cpanel-dovecot-solr".

You can see from the '-Xms' and '-Xmx' directives, it should be fairly limited to 512M. I do recall they stated that it is possible for it to exceed these limits at times, which is why you see the 'OnOutOfMemoryError' directive in the process name. If an OOM event was triggered for this process, you should see the log for it at '/home/cpanelsolr/server/logs/solr_oom_killer*'.

I do find it strange that this would correct your issue. If it did, it may just be a part of your memory issue, and there may be 'Out of memory' errors in '/var/log/messages'.